There must have been something extremely bad about using dual weapons or why hasnt the European nations ever had used them? If they were as great as some of you think then one of the Ancient european superpowers would have used them.
If nobody uses a certain idea, that doesn't mean that it is necessarily a bad idea. Somebody has to be the first after all.
And no, it's not because an idea is known and not being used that it's a bad idea. You just need to find the right way to use it and to train people to do it.
First example I can think of: boolean algebra (based on a paper published in 1854), which is now the base of computer logic, did not really have a relevant application at that time.
